The Sri Lankan authorities have urged islanders near the coast to move at least two kilometres inland, according to reports.

A local news bulletin which interrupted the usual programming schedule read: “An earthquake 8.2 on the Richter scale has been recorded off Sumatra.

“Strong warning of Tsunami tidal wave has been issued. All those within the coastal area in the island are warned to immediately move at least 2km interior.”

Dr Unni Krishnan, Sri Lanka’s emergency co-ordinator for the international charity Action Aid, said many people were evacuating coastal areas in the south of the country.

Speaking from Colombo, he said: “We have been speaking to colleagues in the south and it looks like many people have left the coasts. I don’t know exactly how many people but they are moving away from the sea shores to the interior areas.”

Dr Krishnan said he had heard unconfirmed reports of state sirens alerting people in Trincomalee, on Sri Lanka’s east coast, to move inland.

"We are not certain that there will be another tsunami, but we not taking any chances," Prime Minister Mahinda Rajapakse said. "We have alerted the police to help with the evacuation process." Police chief Chandra Fernando said security has been stepped up to ensure that there was no looting along the coastline.

The December 26 tsunami caused by a powerful submarine earthquake in the Indian Ocean near Indonesia caused widespread destruction and left nearly 31,000 people dead across Sri Lanka.

Local residents along the north-western coastal area of Negombo said people moved to temples and churches and and rang bells to wake up neighbourhoods and ask residents to leave.

Along the island's southern coastal district of Matara, local police urged coastal residents to move inland.

State Rupavahini television network said people should move at least two kilometres away from the east coast while setting a limit of at least one kilometre along the south.